Add Websocket based federation settings, fix key for PurgeExpiredActivity setting

src/views/settings/components/Http.vue

@@ -15,6 +15,10 @@
     <el-form :model="webCacheTtlData" :label-position="labelPosition" :label-width="labelWidth">
       <setting :setting-group="webCacheTtl" :data="webCacheTtlData"/>
     </el-form>
+    <el-divider v-if="fedSockets" class="divider thick-line"/>
+    <el-form :model="fedSocketsData" :label-position="labelPosition" :label-width="labelWidth">
+      <setting :setting-group="fedSockets" :data="fedSocketsData"/>
+    </el-form>
     <div class="submit-button-container">
       <el-button class="submit-button" type="primary" @click="onSubmit">Submit</el-button>
     </div>
@@ -40,6 +44,12 @@ export default {
     corsPlugData() {
       return _.get(this.settings.settings, [':cors_plug']) || {}
     },
+    fedSockets() {
+      return this.settings.description.find(setting => setting.key === ':fed_sockets')
+    },
+    fedSocketsData() {
+      return _.get(this.settings.settings, [':pleroma', ':fed_sockets']) || {}
+    },
     http() {
       return this.settings.description.find(setting => setting.key === ':http')
     },

src/views/settings/components/tabs.js

@@ -26,7 +26,7 @@ export const tabs = description => {
     },
     'http': {
       label: 'settings.http',
-      settings: [':cors_plug', ':http', ':http_security', ':web_cache_ttl']
+      settings: [':cors_plug', ':http', ':fed_sockets', ':http_security', ':web_cache_ttl']
     },
     'instance': {
       label: 'settings.instance',